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Old May 23, 2009, 03:34 AM
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Intermittent XPS operation

I am new the the XPS 2.4 gig system and have an 8 channel Rx mounted in a T Rex 500. At the start all seemed good but before I could complete a range check things started to go bad. Servo operation become very intermittent giving the impression of a flat battery. Changed batteries (3000ma 6S) and again servo response was intermittent. Back home I connected a 4 cell fully charged nicad to the RX and got the same intermittent response. The battery is connected correctly with the negative to the outside. I did a re bind which took about 10 attempts and still no difference. I did a re set and re bind and no difference. However sometimes I will get a good connection, the status light will flash red twice before going green. After a while the servos again will become intermittent. When connecting the battery if the status light flashes red several/many times before going green then the connection will be intermittent. I just tried this. Connected 4 cell nicad and all seems good. Disconnect nicad and power RX from BEC. The speed controller goes through it's sequence of beeps but servo operation is intermittent. Disconnect BEC and re connect nicad. Servo operation is again intermittent. Disconnect nicad and what 10 minutes. Reconnect and all is well again. Connect BEC and all is well. After a few minutes servos beome intermittent. Disconnect BEC and connect nicad and servos are still intermittent. This might be one for Jim.

Thanks
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Old May 24, 2009, 04:52 AM
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Hi there ...

actually - I had exactly the same issue yesterday while trying to test the 2.4GHz system.
After an hour fiddling around on the airfield, I decided I wouldn't take the plane up this day. First power-on, everything worked fine - after about 30secs - while doing the Range-Testing, at about 10m I only had intermittent
reaction. I tried resetting the receiver completely, and rebind to the transmitter. Nothing worked.

Note - I used an old Electro Taxi from Graupner to do the testing.
It's an all Wood Model - and I had no electrics around the receiver at all.

Back home - I did some more tests - the Transmitter and receiver next to each other - and had the same issues.
Tested putting in different power supplies - no change (5x1.25V NiMh batteries, and a BEC System from a JeTi power-regulator unit).
I then decided to try to check with the XtremeLink Device Programmer.
The results were strange. The Transmitter was accessible. I could Read and Write the EEPROM. I could however not use the TxDiag programm to connect to it. Binding was OK, Connecting never worked -> TimeOut.
Regarding the receiver. I was unable to Read/Write the Eprom correctly (as soon as it went into the strange intermittent Operation mode), but connecting it with the RxDiag programm was no problem, and controlling the servos from there went fine all together.
The frequency analyzer showed nothing strange so far. I even disabled my Home-WiFi Systems (as it also runs on 2.4GHz/5GHz combi-mode). Needless to say - no change.

Note that I have used Analog as Digital Servos to test. Both servo Types had the same behavior.
Note 2: Sometimes, a signal passed. However - as I had the aileron Stick completely left - the servo went 100% Left - and it took it sometimes 5 to 10 Seconds until a signal came in to put it back to neutral position - from the moment I left the stick go back to normal.


Equipment used:
- 2.4GHz Graupner Tray Radio Transmitter Module for mc19.
Transmitter set to PPM24Mode because of transmitter 10Channel.
Firmware upraded to latest v3.4
- 2.4GHz XtremeLink® 10 channel receiver.
Firmware upgraded to latest v3.4

Didn't find a 3.3 Upgrade version.

Any hints ?
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Old May 24, 2009, 06:26 AM
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Sounds like you have the same problem as me. I purchased my TX module and 8 channel RX directly from XPS, I am in Australia and there is not local agent. I'm not sure what version I got, would assume it is the lastest. I got vertually no documentation and had to go to the XPS web page to get set procedures etc. My Tx is a JR PCM 10. I'm still no closer to solving the problem. All indications are a battery/voltage problem. I have measured the voltage on the RX at 5.47 volts with the BEC connected. With the 4.8 volt nicad it was 5.42 volts. I increased the BEC output to 5.97 volts and I still have the same problem. I have noted that when the voltage from the nicad drops below 5.0 volts the RX gives a flashing red on power up and will not go green. Seems like the Rx will not operate below 5.0 volts or a least won't power up at this voltage. I have tried disconnecting the servos one at a time and this did not help. I'm using digital servos and have also tried an analog servo with the same intermittent results. It would be good to get some response from Jim Dew.

David
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Old May 24, 2009, 12:16 PM
Xtreme Power Systems
Lake Havasu, AZ
Joined Jun 2005
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What hopping mode are you in? Did you attempt any programming to the receiver (failsafes, channel mapping, etc.)? Are you plugging power into the B/T port or one of the other servo ports?

The TxDiag does not work in hopping modes 2 through 5.

When you power up the receiver, the LED will flash red. When you turn on the transmitter, it will connect. That connection time varies from 80ms to .3 seconds.

When your servos are intermittent, does the LED ever change colors or flicker?

Try doing a RESET to the receiver.
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Old May 24, 2009, 03:22 PM
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Jim I am using the factory pre set hopping mode. I did programme the RX and set the throttle to low for a fail safe. After some consideration I them re set it to hold. This was before the problem first appeared. The BEC gets pluged into the throttle channel and when I connect the 4.8 volt nicad I use the battery port.

When the servos become intermittent the status light stays green and the voltage measured at channel 5 is 5.97 volts.

I did a reset of the receiver and this had no affect.

Last night I reset the BEC output to 5.97 volts. Initially this made no difference and the servos where again intermittent then stoped completely. I turned everything off for 20 minutes and then powered the rx up form the BEC. I could not get the problem to come back after 30 minutes mixing the sticks. I will give it another test after work today.

David
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Old May 24, 2009, 05:32 PM
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Launceston Arpt, Tasmania, Australia
Joined Jan 2004
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Quote:
Originally Posted by JimDrew
What hopping mode are you in? Did you attempt any programming to the receiver (failsafes, channel mapping, etc.)? Are you plugging power into the B/T port or one of the other servo ports?

The TxDiag does not work in hopping modes 2 through 5.

When you power up the receiver, the LED will flash red. When you turn on the transmitter, it will connect. That connection time varies from 80ms to .3 seconds.

When your servos are intermittent, does the LED ever change colors or flicker?

Try doing a RESET to the receiver.
Hi Jim,

could it have anything to do with the Voltage level of your output pulses
being marginal for the type/brand of servos being used?
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Old May 24, 2009, 09:56 PM
Xtreme Power Systems
Lake Havasu, AZ
Joined Jun 2005
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We are aware of only one servo (JR retract servo) that requires a 5.0v input. Our receivers output 3.3v, as do Spektrum and others except Futaba receivers which output 2.7v.
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Old May 25, 2009, 01:58 AM
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Quote:
Originally Posted by JimDrew
What hopping mode are you in? Did you attempt any programming to the receiver (failsafes, channel mapping, etc.)? Are you plugging power into the B/T port or one of the other servo ports?
Hopping mode 4, Level 5 configured.
I did indeed configure the Failsafe etc. before through the Device Programmer (Computer). That worked out fine.
And - the power usually comes in through a normal Servo-Port (BEC System). However - adding any external Battery to the B/T port doesn't make any difference.


Quote:
Originally Posted by JimDrew
The TxDiag does not work in hopping modes 2 through 5.
Correct. Reconfigured the Transmitter to the first in the list - and it worked.

Quote:
Originally Posted by JimDrew
When you power up the receiver, the LED will flash red. When you turn on the transmitter, it will connect. That connection time varies from 80ms to .3 seconds.
This one can take more than 5 seconds until the LED becomes green.
Most of the time it's fast - but it happens to take very long.


Quote:
Originally Posted by JimDrew
When your servos are intermittent, does the LED ever change colors or flicker?
Yes. I had the LED - when the servos are intermittent, that the LED Flashed through all colors. E.g. Red, Orange, Green once. Wasn't able to reproduce it though.

Quote:
Originally Posted by JimDrew
Try doing a RESET to the receiver.
Already resetted it several times.

I also noticed intermittent signals where sent to the servos while no one was touching the Transmitter. And - when moving the servo from one side to the other, stuttering occured. e.g. while changing position, stops for a very short time, then continues. Very odd.
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Old May 25, 2009, 02:10 AM
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Jim, I tested my system again this afternoon and it is still intermittent. On initial turn on everything is good. Gradually the servos become more and more gittery and then stop moving altogether. The status light stays green and voltage is 6.0. I did another re set and re bind but this didn't improve things.

David
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Old May 25, 2009, 03:14 AM
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Tokoroa
Joined Mar 2004
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Where did you measure the voltage?

I suggest you plug another lead into one of the unused receiver ports and measure the voltage at that point. It's not unheard of for a faulty switch harness or connector to introduce a massive voltage drop under load that will not show up when you measure the voltage at the battery end.
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Old May 25, 2009, 03:30 AM
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Where abouts in Aus are you ? be interesting to check with another Rx and Tx unit .......
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Old May 25, 2009, 03:40 AM
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Australia, QLD, King Scrub
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Quote:
Originally Posted by _Peter
Where abouts in Aus are you ? be interesting to check with another Rx and Tx unit .......
If you guys are in Brisbane, I would be happy to help out, I have been using this stuff for years without issue and I have helped a couple of others in our club.

Danny
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Old May 25, 2009, 04:36 AM
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Sale, Victoria, Australia
Joined Oct 2008
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Hey Guys, this is a bit like what I went through a few months ago, have a look at my posts in this thread http://www.rcgroups.com/forums/showt...ht=aussie+bart and follow the bouncing ball with the Aussie Bart postings.

Even though it went away eventually (???), it now seems to have come back on my Yak
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Old May 25, 2009, 06:24 AM
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I measure the voltage off a spare rx port, normally channel 5. I tried a different transmitter, JR PCX 10X but still the same problem. Thanks for the offers of help from Queensland but I'm in Melbourne. As I said before, the problem appears like a battery going flat but voltages are good. I guess it also appears like a lose of range or the tx and rx drifting away from each other. May be it has something to do with the hopping. On turning on the problem comes on slowly to eventually getting no servo response. Turn off for 30 mins and all is good again for a short time. It seems like something heats up, then stops working. Let it cool down then all is well for a short time.

David
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Old May 25, 2009, 07:09 AM
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Just tried again my tests - this time with a voltmeter attached to Pole 10 on my receiver.
The Voltage goes barely under 6.44v even while in heavy movements of all or 1 Servo.

Behavior same as before. Intermittent signal lockups - e.g. LED on receiver Green, no movements as requested through transmitter - however short movements when not requested - like spasmic agonic movements
In the worst case - it takes 2 minutes to position the servo (you read right: 2 Minutes !).

After letting the receiver/trasmitter connected for 5 Minutes - no more immediate reaction at all - can take up to 3 minutes for the reaction to occur - e.g. servo side change. The intermittent convulsions - not linked to any imput - remain though.
Note that after taking out the battery-pack, it took this time well over a minute for the receiver to connect to the transmitter.

I have the feeling that something may be overheating (we have 30C over here). However according to Jim - the components are military grade - so that temperature should do nothing ... This behavior is however a very strong evidence for overheating (having a Long time computer experience).

Anything else I could do to test ?
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